Of the sawdust produced in the operation of power saws the heavier, larger particles are thrown in some more or less finite direction by the saw blade and may be collected in a suitably positioned receptacle while fine particles thereof become airborne to be inhaled by the operator or drift with air currents to eventually accumulate in areas remote from the workshop. When the workshop is located in a residence accumulations of fine sawdust remote from the workshop becomes a major problem.
The volume of fine sawdust particles likely to become airborne is quite small compared to the volume of larger heavier particles produced in sawing so that the capacity of means for collecting only these finer particles may be made commensurate. When a centrifugal blower is employed to provide a vacuum for collecting only these finer sawdust particles from confined areas wherein both fine and larger, heavier sawdust particles are present it is essential to determine a discriminating airflow speed through these areas. Too high an airflow speed will of course load the blower and collecting receptacle with the larger, heavier particles which may readily be collected by other means also, in some instances a high airflow rate may draw into the blower larger pieces of the wood being sawed thereby clogging the blower. Centrifugal blower means and its connections with these confined areas which will result in an airflow speed through these areas just sufficient to collect only the finer particles of sawdust is a feature of this invention.